[SCTP]: ADDIP: Don't use an address as source until it is ASCONF-ACKed

This implements Rules D1 and D4 of Sec 4.3 in the ADDIP draft.

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 80 insertions, 27 deletions

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 268f2e19ccbb..e5aa7ff1f5b5 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -731,13 +731,10 @@ void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
 
 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
-/* sin_family -- AF_INET or AF_INET6
- * sin_port -- ordinary port number
- * sin_addr -- cast to either (struct in_addr) or (struct in6_addr)
- */
 struct sctp_sockaddr_entry {
         struct list_head list;
         union sctp_addr a;
+        __u8 use_as_src;
 };
 
 typedef struct sctp_chunk *(sctp_packet_phandler_t)(struct sctp_association *);
@@ -1142,7 +1139,7 @@ int sctp_bind_addr_copy(struct sctp_bind_addr *dest,
                         sctp_scope_t scope, gfp_t gfp,
                         int flags);
 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
-                       gfp_t gfp);
+                       __u8 use_as_src, gfp_t gfp);
 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
                          struct sctp_sock *);
diff --git a/net/sctp/bind_addr.c b/net/sctp/bind_addr.c
index 2b962627f631..2b9c12a170e5 100644
--- a/net/sctp/bind_addr.c
+++ b/net/sctp/bind_addr.c
@@ -146,7 +146,7 @@ void sctp_bind_addr_free(struct sctp_bind_addr *bp)
 
 /* Add an address to the bind address list in the SCTP_bind_addr structure. */
 int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,
-                       gfp_t gfp)
+                       __u8 use_as_src, gfp_t gfp)
 {
         struct sctp_sockaddr_entry *addr;
 
@@ -163,6 +163,8 @@ int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,
         if (!addr->a.v4.sin_port)
                 addr->a.v4.sin_port = bp->port;
 
+        addr->use_as_src = use_as_src;
+
         INIT_LIST_HEAD(&addr->list);
         list_add_tail(&addr->list, &bp->address_list);
         SCTP_DBG_OBJCNT_INC(addr);
@@ -274,7 +276,7 @@ int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw_addr_list,
                 }
 
                 af->from_addr_param(&addr, rawaddr, port, 0);
-                retval = sctp_add_bind_addr(bp, &addr, gfp);
+                retval = sctp_add_bind_addr(bp, &addr, 1, gfp);
                 if (retval) {
                         /* Can't finish building the list, clean up. */
                         sctp_bind_addr_clean(bp);
@@ -367,7 +369,7 @@ static int sctp_copy_one_addr(struct sctp_bind_addr *dest,
                     (((AF_INET6 == addr->sa.sa_family) &&
                       (flags & SCTP_ADDR6_ALLOWED) &&
                       (flags & SCTP_ADDR6_PEERSUPP))))
-                        error = sctp_add_bind_addr(dest, addr, gfp);
+                        error = sctp_add_bind_addr(dest, addr, 1, gfp);
         }
 
         return error;
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index 8ef08070c8b6..99c0cefc04e0 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -290,7 +290,8 @@ static void sctp_v6_get_saddr(struct sctp_association *asoc,
         sctp_read_lock(addr_lock);
         list_for_each(pos, &bp->address_list) {
                 laddr = list_entry(pos, struct sctp_sockaddr_entry, list);
-                if ((laddr->a.sa.sa_family == AF_INET6) &&
+                if ((laddr->use_as_src) &&
+                    (laddr->a.sa.sa_family == AF_INET6) &&
                     (scope <= sctp_scope(&laddr->a))) {
                         bmatchlen = sctp_v6_addr_match_len(daddr, &laddr->a);
                         if (!baddr || (matchlen < bmatchlen)) {
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 816c033d7886..1ab03a27a76e 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -240,7 +240,7 @@ int sctp_copy_local_addr_list(struct sctp_bind_addr *bp, sctp_scope_t scope,
                             (((AF_INET6 == addr->a.sa.sa_family) &&
                               (copy_flags & SCTP_ADDR6_ALLOWED) &&
                               (copy_flags & SCTP_ADDR6_PEERSUPP)))) {
-                                error = sctp_add_bind_addr(bp, &addr->a, 
+                                error = sctp_add_bind_addr(bp, &addr->a, 1,
                                                            GFP_ATOMIC);
                                 if (error)
                                         goto end_copy;
@@ -486,6 +486,8 @@ static struct dst_entry *sctp_v4_get_dst(struct sctp_association *asoc,
                 list_for_each(pos, &bp->address_list) {
                         laddr = list_entry(pos, struct sctp_sockaddr_entry,
                                            list);
+                        if (!laddr->use_as_src)
+                                continue;
                         sctp_v4_dst_saddr(&dst_saddr, dst, bp->port);
                         if (sctp_v4_cmp_addr(&dst_saddr, &laddr->a))
                                 goto out_unlock;
@@ -506,7 +508,8 @@ static struct dst_entry *sctp_v4_get_dst(struct sctp_association *asoc,
         list_for_each(pos, &bp->address_list) {
                 laddr = list_entry(pos, struct sctp_sockaddr_entry, list);
 
-                if (AF_INET == laddr->a.sa.sa_family) {
+                if ((laddr->use_as_src) &&
+                    (AF_INET == laddr->a.sa.sa_family)) {
                         fl.fl4_src = laddr->a.v4.sin_addr.s_addr;
                         if (!ip_route_output_key(&rt, &fl)) {
                                 dst = &rt->u.dst;
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 8134e8b1cdca..4f11f5858209 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -1493,7 +1493,7 @@ no_hmac:
 
         /* Also, add the destination address. */
         if (list_empty(&retval->base.bind_addr.address_list)) {
-                sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
+                sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest, 1,
                                    GFP_ATOMIC);
         }
 
@@ -2565,6 +2565,7 @@ static int sctp_asconf_param_success(struct sctp_association *asoc,
         union sctp_addr_param *addr_param;
         struct list_head *pos;
         struct sctp_transport *transport;
+        struct sctp_sockaddr_entry *saddr;
         int retval = 0;
 
         addr_param = (union sctp_addr_param *)
@@ -2578,7 +2579,11 @@ static int sctp_asconf_param_success(struct sctp_association *asoc,
         case SCTP_PARAM_ADD_IP:
                 sctp_local_bh_disable();
                 sctp_write_lock(&asoc->base.addr_lock);
-                retval = sctp_add_bind_addr(bp, &addr, GFP_ATOMIC);
+                list_for_each(pos, &bp->address_list) {
+                        saddr = list_entry(pos, struct sctp_sockaddr_entry, list);
+                        if (sctp_cmp_addr_exact(&saddr->a, &addr))
+                                saddr->use_as_src = 1;
+                }
                 sctp_write_unlock(&asoc->base.addr_lock);
                 sctp_local_bh_enable();
                 break;
@@ -2591,6 +2596,7 @@ static int sctp_asconf_param_success(struct sctp_association *asoc,
                 list_for_each(pos, &asoc->peer.transport_addr_list) {
                         transport = list_entry(pos, struct sctp_transport,
                                                  transports);
+                        dst_release(transport->dst);
                         sctp_transport_route(transport, NULL,
                                              sctp_sk(asoc->base.sk));
                 }
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 518c55ab610b..54722e622e6d 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -369,7 +369,7 @@ SCTP_STATIC int sctp_do_bind(struct sock *sk, union sctp_addr *addr, int len)
 
         /* Use GFP_ATOMIC since BHs are disabled.  */
         addr->v4.sin_port = ntohs(addr->v4.sin_port);
-        ret = sctp_add_bind_addr(bp, addr, GFP_ATOMIC);
+        ret = sctp_add_bind_addr(bp, addr, 1, GFP_ATOMIC);
         addr->v4.sin_port = htons(addr->v4.sin_port);
         sctp_write_unlock(&ep->base.addr_lock);
         sctp_local_bh_enable();
@@ -491,6 +491,7 @@ static int sctp_send_asconf_add_ip(struct sock		*sk,
         struct sctp_chunk               *chunk;
         struct sctp_sockaddr_entry      *laddr;
         union sctp_addr                 *addr;
+        union sctp_addr                 saveaddr;
         void                            *addr_buf;
         struct sctp_af                  *af;
         struct list_head                *pos;
@@ -558,14 +559,26 @@ static int sctp_send_asconf_add_ip(struct sock		*sk,
                 }
 
                 retval = sctp_send_asconf(asoc, chunk);
+                if (retval)
+                        goto out;
 
-                /* FIXME: After sending the add address ASCONF chunk, we
-                 * cannot append the address to the association's binding
-                 * address list, because the new address may be used as the
-                 * source of a message sent to the peer before the ASCONF
-                 * chunk is received by the peer.  So we should wait until
-                 * ASCONF_ACK is received.
+                /* Add the new addresses to the bind address list with
+                 * use_as_src set to 0.
                  */
+                sctp_local_bh_disable();
+                sctp_write_lock(&asoc->base.addr_lock);
+                addr_buf = addrs;
+                for (i = 0; i < addrcnt; i++) {
+                        addr = (union sctp_addr *)addr_buf;
+                        af = sctp_get_af_specific(addr->v4.sin_family);
+                        memcpy(&saveaddr, addr, af->sockaddr_len);
+                        saveaddr.v4.sin_port = ntohs(saveaddr.v4.sin_port);
+                        retval = sctp_add_bind_addr(bp, &saveaddr, 0,
+                                                    GFP_ATOMIC);
+                        addr_buf += af->sockaddr_len;
+                }
+                sctp_write_unlock(&asoc->base.addr_lock);
+                sctp_local_bh_enable();
         }
 
 out:
@@ -676,12 +689,15 @@ static int sctp_send_asconf_del_ip(struct sock		*sk,
         struct sctp_sock        *sp;
         struct sctp_endpoint    *ep;
         struct sctp_association *asoc;
+        struct sctp_transport   *transport;
         struct sctp_bind_addr   *bp;
         struct sctp_chunk       *chunk;
         union sctp_addr         *laddr;
+        union sctp_addr         saveaddr;
         void                    *addr_buf;
         struct sctp_af          *af;
-        struct list_head        *pos;
+        struct list_head        *pos, *pos1;
+        struct sctp_sockaddr_entry *saddr;
         int                     i;
         int                     retval = 0;
 
@@ -748,14 +764,42 @@ static int sctp_send_asconf_del_ip(struct sock		*sk,
                         goto out;
                 }
 
-                retval = sctp_send_asconf(asoc, chunk);
+                /* Reset use_as_src flag for the addresses in the bind address
+                 * list that are to be deleted.
+                 */
+                sctp_local_bh_disable();
+                sctp_write_lock(&asoc->base.addr_lock);
+                addr_buf = addrs;
+                for (i = 0; i < addrcnt; i++) {
+                        laddr = (union sctp_addr *)addr_buf;
+                        af = sctp_get_af_specific(laddr->v4.sin_family);
+                        memcpy(&saveaddr, laddr, af->sockaddr_len);
+                        saveaddr.v4.sin_port = ntohs(saveaddr.v4.sin_port);
+                        list_for_each(pos1, &bp->address_list) {
+                                saddr = list_entry(pos1,
+                                                   struct sctp_sockaddr_entry,
+                                                   list);
+                                if (sctp_cmp_addr_exact(&saddr->a, &saveaddr))
+                                        saddr->use_as_src = 0;
+                        }
+                        addr_buf += af->sockaddr_len;
+                }
+                sctp_write_unlock(&asoc->base.addr_lock);
+                sctp_local_bh_enable();
 
-                /* FIXME: After sending the delete address ASCONF chunk, we
-                 * cannot remove the addresses from the association's bind
-                 * address list, because there maybe some packet send to
-                 * the delete addresses, so we should wait until ASCONF_ACK
-                 * packet is received.
+                /* Update the route and saddr entries for all the transports
+                 * as some of the addresses in the bind address list are
+                 * about to be deleted and cannot be used as source addresses.
                  */
+                list_for_each(pos1, &asoc->peer.transport_addr_list) {
+                        transport = list_entry(pos1, struct sctp_transport,
+                                               transports);
+                        dst_release(transport->dst);
+                        sctp_transport_route(transport, NULL,
+                                             sctp_sk(asoc->base.sk));
+                }
+
+                retval = sctp_send_asconf(asoc, chunk);
         }
 out:
         return retval;